Tips and Helpful Links for NPDES Permit Applications for Small POTWs
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This page provides instructions and tips for applying for a National Pollutant Discharge Elimination System (NPDES) permit for a publicly owned treatment works (POTW) from EPA Region 10, with emphasis on POTWs with design flows less than 1 million gallons per day (mgd). All facilities, including POTWs, which discharge pollutants to waters of the United States, are required to obtain an NPDES permit. NPDES permits limit the amount of pollution discharged into surface waters.
In most states, the NPDES permit program is administered by the state government, however, in Idaho, EPA Region 10 currently administers the program. EPA Region 10 also issues a few specific kinds of NPDES permits in Alaska, Oregon, and Washington (for example, permits for Tribal facilities and POTWs with "301(h)" waivers from secondary treatment). There is no fee associated with the application for an NPDES permit from EPA Region 10.
NPDES "Form 2A" Permit Application for POTWs (PDF) (23 pp, 374K)
Federal Register Instructions
Detailed instructions regarding the application process for POTWs (PDF) (9 pp, 48 K) were published in the Federal Register in 1999. All sections of the NPDES permit application are explained in the Federal Register instructions.
POTWs with a design flow less than 100,000 gallons per day (0.1 mgd) are only required to fill out parts A and C of the application. POTWs with design flows of at least 0.1 mgd but less than 1 mgd are also required to fill out part B of the application. Larger POTWs, and POTWs required to have a pretreatment program, are also required to fill out parts D, E, and F of the application.
This page supplements the Federal Register instructions for Parts A, B, and C of the application form.
In general, you must apply for a permit at least 180 days before the expiration date of your existing permit (if you have one), or at least 180 days before you plan to begin a new discharge. If you cannot meet these deadlines, please contact us before the deadline to discuss permission for a later date.
Tips and Links
We understand that the NPDES permit application process can be overwhelming. Contact us with any questions you may have as you proceed through this process. The following links are also meant to provide you with helpful resources and information.
Part A -- Required for All POTWs
Part A.9 Description of Outfall
Accurate latitude and longitude of point source outfalls must be included in part A.9.
Mapquest and Bing Maps are two examples of websites that provide latitude and longitude coordinates. To find the latitude and longitude of your outfall using these sites, simply find the location of the outfall on the map, right-click on the map at that location, and the latitude and longitude coordinates will appear, along with the nearest street address.
If you have a smartphone or tablet equipped with GPS, free or low-cost applications are available that can display the latitude and longitude of your current location.
If you are using a paper map, latitude will be shown on lines running horizontally across the map, while longitude will be shown with vertical lines. Pinpoint your location and note the degrees written on these lines to determine the latitude and longitude of the outfall.
Part A.10 Description of Receiving Waters
Within part A.10, the following information is helpful to expedite the permit process, although it is not required:
- The name of the receiving watershed (b), as well as United States Geological Survey (USGS) 8 digit watershed codes (c) can be found on the EPA’s Surf Your Watershed page.
- Data on critical low flow (d) can be accessed using the USGS StreamStats program, which allows you to access stream flow statistics for various sites within the state of Idaho using an interactive map.
- Water hardness (e) can be measured through a sample at any water test lab facility, however the USGS may have already measured the hardness of your receiving water. Refer to this list of USGS monitoring stations in Idaho with hardness data.
Part B -- Required for POTWs with Design Flows of At Least 0.1 mgd
Part B.1 Inflow and Infiltration
Please remember to include an estimate of the average daily flow rate of inflow and infiltration in gallons per day including steps the facility is taking to minimize inflow and infiltration. Refer to EPA Region 1’s Quick Guide for Estimating Infiltration and Inflow (PDF) (3 pp, 507 K).
Part B.2 Topographic Map
Topographic maps are available through various web sites including the USGS Store.
Please remember to include a map extending at least 1 mile beyond the property boundaries of the facility, displaying major pipes and wastewater structures including wells, springs, and other surface water bodies. The map must also illustrate the location at which waste enters the facility.
Part B.3 Process Flow Diagram or Schematic
Within section B.3, please include both a diagram and written explanation illustrating flow and treatment processes. The process flow diagram indicates the general operations and methods of treatment and must include all piping and power sources as well as all treatment units including disinfection, daily average flow rates at influent and discharging points, and approximate daily flow rates. Refer to these examples of a flow diagram (PDF) (1 pg, 154 K) and narrative description (PDF) (1 pg, 39 K).
Part B.6 Effluent Testing
Data must be submitted for all of the pollutants listed in part B.6 of the application. Even if routine testing of some of the listed compounds is not done at regular intervals, please provide data for all eight of the specific pollutants listed on the application. Detailed instructions for reporting effluent testing data are provided in Appendix A to the Federal Register Instructions (PDF) (9 pp, 48 K). When collecting and reporting effluent testing data, NPDES applicants must use sufficiently sensitive (PDF) (1 pg, 261 K) EPA-approved analytical methods that are capable of detecting and measuring the pollutants at, or below, the applicable water quality criteria or permit limits.
Part C -- Required for All POTWs
All applications must include a certified signature by a ranking elected official (e.g., Mayor) or appointed official (e.g., Director of Public Works). Refer to the Code of Federal Regulations at 40 CFR 122.22.
Please send completed forms to:
NPDES Permits Unit
US EPA Region 10
1200 Sixth Avenue
Suite 900 M/S OWW-191
Seattle, WA 98101